''Cronobacter'' is a genus of

Gram-negative Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wall ...

facultatively anaerobic A facultative anaerobic organism is an organism that makes ATP by aerobic respiration if oxygen is present, but is capable of switching to fermentation if oxygen is absent. Some examples of facultatively anaerobic bacteria are ''Staphylococcus' ...

oxidase In biochemistry, an oxidase is an enzyme that catalyzes oxidation-reduction reactions, especially one involving dioxygen (O2) as the electron acceptor. In reactions involving donation of a hydrogen atom, oxygen is reduced to water (H2O) or hydro ...

-negative,

catalase Catalase is a common enzyme found in nearly all living organisms exposed to oxygen (such as bacteria, plants, and animals) which catalyzes the decomposition of hydrogen peroxide to water and oxygen. It is a very important enzyme in protecting t ...

-positive,

rod-shaped A bacillus (), also called a bacilliform bacterium or often just a rod (when the context makes the sense clear), is a rod-shaped bacterium or archaeon. Bacilli are found in many different taxonomic groups of bacteria. However, the name ''Bacillu ...

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...

of the family

Enterobacteriaceae Enterobacteriaceae is a large family (biology), family of Gram-negative bacteria. It was first proposed by Rahn in 1936, and now includes over 30 genera and more than 100 species. Its classification above the level of family is still a subject ...

. Several ''Cronobacter'' species are desiccation resistant and persistent in dry products such as powdered infant formula. They are generally motile, reduce

nitrate Nitrate is a polyatomic ion A polyatomic ion, also known as a molecular ion, is a covalent bonded set of two or more atoms, or of a metal complex, that can be considered to behave as a single unit and that has a net charge that is not zer ...

, use

citrate Citric acid is an organic compound with the chemical formula HOC(CO2H)(CH2CO2H)2. It is a colorless weak organic acid. It occurs naturally in citrus fruits. In biochemistry, it is an intermediate in the citric acid cycle, which occurs in t ...

, hydrolyze

esculin Aesculin, also called æsculin or esculin, is a coumarin glucoside that naturally occurs in the trees Horse-chestnut (tree), horse chestnut (''Aesculus hippocastanum''), California buckeye (''Aesculus californica''), prickly box (''Bursaria spinos ...

and

arginine Arginine is the amino acid with the formula (H2N)(HN)CN(H)(CH2)3CH(NH2)CO2H. The molecule features a guanidino group appended to a standard amino acid framework. At physiological pH, the carboxylic acid is deprotonated (−CO2−) and both the am ...

, and are positive for L-

ornithine Ornithine is a non-proteinogenic amino acid that plays a role in the urea cycle. Ornithine is abnormally accumulated in the body in ornithine transcarbamylase deficiency. The radical is ornithyl. Role in urea cycle L-Ornithine is one of the produ ...

decarboxylation Decarboxylation is a chemical reaction that removes a carboxyl group and releases carbon dioxide (CO2). Usually, decarboxylation refers to a reaction of carboxylic acids, removing a carbon atom from a carbon chain. The reverse process, which is t ...

. Acid is produced from D-

glucose Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using ...

, D-

sucrose Sucrose, a disaccharide, is a sugar composed of glucose and fructose subunits. It is produced naturally in plants and is the main constituent of white sugar. It has the molecular formula . For human consumption, sucrose is extracted and refined ...

, D-

raffinose Raffinose is a trisaccharide composed of galactose, glucose, and fructose. It can be found in beans, cabbage, brussels sprouts, broccoli, asparagus, other vegetables, and whole grains. Raffinose can be hydrolyzed to D-galactose and sucrose by ...

, D-

melibiose Melibiose is a reducing disaccharide formed by an α-1,6 linkage between galactose and glucose (D-Gal-α(1→6)-D-Glc). It differs from lactose in the chirality of the carbon where the galactose ring is closed and that the galactose is linked to a ...

, D-

cellobiose Cellobiose is a disaccharide with the formula (C6H7(OH)4O)2O. It is classified as a reducing sugar. In terms of its chemical structure, it is derived from the condensation of a pair of β-glucose molecules forming a β(1→4) bond. It can be hyd ...

, D-

mannitol Mannitol is a type of sugar alcohol used as a sweetener and medication. It is used as a low calorie sweetener as it is poorly absorbed by the intestines. As a medication, it is used to decrease pressure in the eyes, as in glaucoma, and to lower ...

, D-

mannose Mannose is a sugar monomer of the aldohexose series of carbohydrates. It is a C-2 epimer of glucose. Mannose is important in human metabolism, especially in the glycosylation of certain proteins. Several congenital disorders of glycosylation ...

, L-

rhamnose Rhamnose (Rha, Rham) is a naturally occurring deoxy sugar. It can be classified as either a methyl-pentose or a 6-deoxy-hexose. Rhamnose predominantly occurs in nature in its L-form as L-rhamnose (6-deoxy-L-mannose). This is unusual, since most o ...

, L-

arabinose Arabinose is an aldopentose – a monosaccharide containing five carbon atoms, and including an aldehyde (CHO) functional group. For biosynthetic reasons, most saccharides are almost always more abundant in nature as the "D"-form, or structurally ...

, D-

trehalose Trehalose (from Turkish '' tıgala'' – a sugar derived from insect cocoons + -ose) is a sugar consisting of two molecules of glucose. It is also known as mycose or tremalose. Some bacteria, fungi, plants and invertebrate animals synthesize it ...

, galacturonate and D-

maltose } Maltose ( or ), also known as maltobiose or malt sugar, is a disaccharide formed from two units of glucose joined with an α(1→4) bond. In the isomer isomaltose, the two glucose molecules are joined with an α(1→6) bond. Maltose is the two- ...

. ''Cronobacter'' spp. are also generally positive for

acetoin Acetoin, also known as 3-hydroxybutanone or acetyl methyl carbinol, is an organic compound with the formula CH3CH(OH)C(O)CH3. It is a colorless liquid with a pleasant, buttery odor. It is chiral. The form produced by bacteria is (''R'')-acetoin. ...

production ( Voges–Proskauer test) and negative for the

methyl red Methyl red (2-(''N'',''N''-dimethyl-4-aminophenyl) azobenzenecarboxylic acid), also called C.I. Acid Red 2, is an indicator dye that turns red in acidic solutions. It is an azo dye, and is a dark red crystalline powder. Methyl red is a pH indic ...

test, indicating

2,3-butanediol 2,3-Butanediol is the organic compound with the formula (CH3CHOH)2. It is classified as a ''vic''-diol (glycol). It exists as three stereoisomers, a chiral pair and the meso isomer. All are colorless liquids. Applications include precursors to ...

rather than

mixed acid fermentation In biochemistry, mixed acid fermentation is the metabolic process by which a six-carbon sugar (e.g. glucose, ) is converted into a complex and variable mixture of acids. It is an anaerobic (non-oxygen-requiring) fermentation reaction that is ...

. The type species of the genus ''Cronobacter'' is ''Cronobacter sakazakii'' comb. nov.

Clinical significance

All ''Cronobacter'' species, except ''C. condimenti'', have been linked retrospectively to clinical cases of infection. While cases of infection do occur in adults, these are generally non-life-threatening, and often secondary colonization to underlying health problems. Infection in infants is associated with

neonatal An infant or baby is the very young offspring of human beings. ''Infant'' (from the Latin word ''infans'', meaning 'unable to speak' or 'speechless') is a formal or specialised synonym for the common term ''baby''. The terms may also be used to ...

bacteraemia Bloodstream infections (BSIs), which include bacteremias when the infections are bacterial and fungemias when the infections are fungal, are infections present in the blood. Blood is normally a sterile environment, so the detection of micro ...

meningitis Meningitis is acute or chronic inflammation of the protective membranes covering the brain and spinal cord, collectively called the meninges. The most common symptoms are fever, headache, and neck stiffness. Other symptoms include confusion or ...

and

necrotising enterocolitis Necrotizing enterocolitis (NEC) is a devastating intestinal disease that affects premature or very low birth weight infants.Gephart S.M., Quinn M. A call to action to fight for equity and end necrotizing enterocolitis disparities. ''Adv. Neonata ...

with a high case fatality rate and ongoing disablement of survivors. Increased awareness that ''Cronobacter'' are ubiquitous environmental organisms, initiatives by the

WHO Who or WHO may refer to: * Who (pronoun), an interrogative or relative pronoun * Who?, one of the Five Ws in journalism * World Health Organization Arts and entertainment Fictional characters * Who, a creature in the Dr. Seuss book ''Horton Hear ...

and

FAO The Food and Agriculture Organization of the United Nations (FAO)french: link=no, Organisation des Nations unies pour l'alimentation et l'agriculture; it, Organizzazione delle Nazioni Unite per l'Alimentazione e l'Agricoltura is an intern ...

, and advice on infant feeding (including safe temperatures for reconstitution of powdered infant formula, and appropriate hold times, post-reconstitution) has drastically reduced the occurrence of infection outbreaks. Additionally, the introduction of an

ISO ISO is the most common abbreviation for the International Organization for Standardization. ISO or Iso may also refer to: Business and finance * Iso (supermarket), a chain of Danish supermarkets incorporated into the SuperBest chain in 2007 * Iso ...

standard method for detection of these organisms has aided the infant formula industry to control their presence in manufacturing sites and products, further reducing the risk to infants. However, isolated cases can still occur, in part due to ''Cronobacter'' being ubiquitous in home environments as well.

Taxonomy

''Cronobacter'' was first proposed as a new genus in 2007 as a clarification of the taxonomic relationship of the biogroups found among strains of '' Enterobacter sakazakii''. This proposal was validly published in 2008 with five species and three subspecies named. The genus definition was further revised in 2012 to seven named species when a name (''C. universalis'') was given to a group of isolates that were deemed too few in number to accurately describe during the original taxonomic work, and a single additional isolate was also named (''C. condimenti''). In 2013 ''Enterobacter helveticus'', ''Enterobacter pulveris'' and ''Enterobacter turicensis'' were reclassified into the genus ''Cronobacter'', however this was corrected in 2014 when Stephan ''et al.'' published evidence that these should be classified as '' Franconibacter helveticus'', '' Franconibacter pulveris'' and '' Siccibacter turicensis'' respectively.

Etymology

''Cronobacter'' (Cro.no.bac'ter) is from the Greek noun '' Cronos'' (Κρόνος), one of the

Titans In Greek mythology, the Titans ( grc, οἱ Τῑτᾶνες, ''hoi Tītânes'', , ''ho Tītân'') were the pre-Olympian gods. According to the ''Theogony'' of Hesiod, they were the twelve children of the primordial parents Uranus (Sky) and Ga ...

of mythology, who swallowed each of his children as soon as they were born, and the New Latin masculine noun ''bacter'', a rod, resulting in the N.L. masc. n. Cronobacter, a rod that can cause illness in neonates. ''Cronobacter sakazakii'' (sak.a.zaki.ī. N.L. gen. n. sakazakii, of Sakazaki) is named in honour of the Japanese microbiologist Riichi Sakazaki ( ja: 坂崎利一). ''Cronobacter malonaticus'' (mă.lō.nă.tĭ'cŭs) is from N.L. n. ''malonas'' ''-atis'', malonate; L. suff. ''-icus'', suffix used with the sense of belonging to; N.L. masc. adj. ''malonaticus'', pertaining to the use of

malonate The conjugate acids are in :Carboxylic acids. {{Commons category, Carboxylate ions, Carboxylate anions Carbon compounds Oxyanions ...

. The type strain, CDC 1058-77T, was isolated from a breast abscess. ''Cronobacter turicensis'' (tŭ.rĭ.sĕn'sĭs) is from the L. masc. adj. ''turicensis'', pertaining to ''Turicum'', the Latin name of Zurich, Switzerland. ''Cronobacter muytjensii'' (mœ.tjәn.sĭ.ī), from the N.L. gen. n. ''muytjensii'', of Muytjens, is named in honour of the Dutch microbiologist Harry Muytjens, who performed much of the early work on ''Enterobacter sakazakii''. ''Cronobacter dublinensis'' (dŭb.lĭn.ĕn'sĭs, from the N.L. masc. adj. ''dublinensis'', pertains to

Dublin Dublin (; , or ) is the capital and largest city of Republic of Ireland, Ireland. On a bay at the mouth of the River Liffey, it is in the Provinces of Ireland, province of Leinster, bordered on the south by the Dublin Mountains, a part of th ...

, Ireland, the origin of the type strain. ''C. dublinensis'' subsp. ''lausannensis'' (lô.săn.ĕn'sĭs) from the L. masc. adj. ''lausannensis'', pertains to

Lausanne , neighboring_municipalities= Bottens, Bretigny-sur-Morrens, Chavannes-près-Renens, Cheseaux-sur-Lausanne, Crissier, Cugy, Écublens, Épalinges, Évian-les-Bains (FR-74), Froideville, Jouxtens-Mézery, Le Mont-sur-Lausanne, Lugrin (FR-74), ...

, Switzerland, the origin of the type strain for this subspecies. ''C. dublinensis'' subsp. ''lactaridi '' (lăkt.ărĭd.ī), is from the L. n. lac ''lactis'', milk, L. adj. ''aridus'', dried, to give N.L. gen. n. ''lactaridi'', of a dried milk. ''Cronobacter universalis'' (u.ni.ver.sa'lis) is L. masc. adj. ''universalis'', of or belonging to all or universal. ''Cronobacter condimenti'' (con.di.men'ti) is from the L. gen. n. ''condimenti'', of spice or seasoning, as it was first isolated in part from spiced meat.

References

{{Taxonbar, from=Q311419 Enterobacteriaceae Bacteria genera

Clinical significance

Taxonomy

Etymology

See also

References